example_unix_test.go

     1  // Copyright 2020 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build unix
     6  
     7  package signal_test
     8  
     9  import (
    10  	"context"
    11  	"fmt"
    12  	"log"
    13  	"os"
    14  	"os/signal"
    15  	"time"
    16  )
    17  
    18  // This example passes a context with a signal to tell a blocking function that
    19  // it should abandon its work after a signal is received.
    20  func ExampleNotifyContext() {
    21  	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
    22  	defer stop()
    23  
    24  	p, err := os.FindProcess(os.Getpid())
    25  	if err != nil {
    26  		log.Fatal(err)
    27  	}
    28  
    29  	// On a Unix-like system, pressing Ctrl+C on a keyboard sends a
    30  	// SIGINT signal to the process of the program in execution.
    31  	//
    32  	// This example simulates that by sending a SIGINT signal to itself.
    33  	if err := p.Signal(os.Interrupt); err != nil {
    34  		log.Fatal(err)
    35  	}
    36  
    37  	select {
    38  	case <-time.After(time.Second):
    39  		fmt.Println("missed signal")
    40  	case <-ctx.Done():
    41  		fmt.Println(ctx.Err()) // prints "context canceled"
    42  		stop()                 // stop receiving signal notifications as soon as possible.
    43  	}
    44  
    45  	// Output:
    46  	// context canceled
    47  }
    48
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